Remove the tofu from its package and place it on a wire rack set over a tray. Allow it to drain for at least one hour to remove excess water. This drying process helps create an exceptionally crispy exterior during frying.
Place the drained tofu on several layers of paper towels and cut it into nine evenly sized cubes. Sprinkle salt over all sides of the tofu cubes. Let them sit while you prepare the sauce so the salt can draw out additional surface moisture.
Grate the ginger and squeeze the juice into a saucepan, discarding the fibrous pulp. Add the grated garlic, mirin, soy sauce, and black pepper. Bring the mixture to a boil over high heat and cook for about one minute until slightly thickened and fragrant. Transfer the glaze to a bowl and set aside
Pour about two inches of vegetable oil into a heavy-bottomed pot. Heat the oil until it reaches 360°F (180°C). Maintaining the correct frying temperature is important because it quickly crisps the tofu without making it greasy.
Before frying, pat every side of the tofu cubes with fresh paper towels. Removing as much surface moisture as possible minimizes splattering and helps the tofu develop a beautifully crisp crust.
Carefully lower the tofu cubes into the hot oil using tongs. Fry them undisturbed for about five to six minutes until they naturally release from the bottom of the pot. Turn them gently and continue frying until all sides are golden brown and crispy.
Transfer the hot tofu directly from the oil into the bowl of prepared glaze. Sprinkle in the toasted sesame seeds and gently toss everything together. The hot tofu absorbs the glaze beautifully while remaining crisp.
Move the glazed tofu bites onto a serving plate immediately. Garnish with extra sesame seeds, freshly ground black pepper, and chopped scallion greens. Serve while hot for the best texture and flavor.